2014-10-28

28 MHz OTHR intruder

Spectrum 27900-28100 kHz on 2014-10-28 at 0813 UTC

This is the spectrum of a particularly obnoxious intruder which infests 28 MHz (10 m) during times of high MUF. It is a screenshot taken this morning using my Peresus SDR receiver and a multiband vertical antenna. It is centered on 28000 kHz and it shows that the intruder wipes out the lower 25 kHz of the CW portion of the band.

Possibly some kind of Over the Horizon Radar (OHTR), it is apporximately 50 kHz wide and is usually found near 28.000 or 28.500. It affected the CQ WW SSB contest last weekend, when it transmitted near 28.600 kHz.The FM (F3E) signal near 28055 kHz is a taxi dispather in Russia.See also: IARU Region 1 monitoring system .